diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -55,3 +55,7 @@
 
 * Fifth version. Added more command line options like "-h" and "-v". New module 
 dependencies. Fixed issues with the deprecated wrong documentation.
+
+## 0.5.1.0. -- 2020-01-16
+
+* Fifth version revised A. Fixed issue with threads. Now, mmsyn7h must run without blocking the other Haskell threads.
diff --git a/mmsyn7h.cabal b/mmsyn7h.cabal
--- a/mmsyn7h.cabal
+++ b/mmsyn7h.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                mmsyn7h
-version:             0.5.0.0
+version:             0.5.1.0
 synopsis:            Produces a sound recording specified by the Ukrainian text.
 description:         A program and a library that are used with mmsyn7ukr (or separately) and are similar to mmsyn6ukr executable. The program uses the data files in the current directory instead of ones in the system defined directories. It reads Ukrainian text with the given by data files sounds.
 homepage:            https://hackage.haskell.org/package/mmsyn7h
@@ -30,5 +30,6 @@
   -- other-modules:
   -- other-extensions:
   build-depends:       base >=4.7 && <4.14, process >=1.4 && <1.8, vector >=0.11 && <0.14, bytestring >=0.10 && <0.12, mmsyn2 >=0.1.7 && <1, directory >=1.2.5 && <1.4, mmsyn6ukr >=0.6.2 && <1, mmsyn3 >=0.1.4 && <1, mmsyn7s >=0.1 && <1
+  ghc-options:         -threaded  
   -- hs-source-dirs:
   default-language:    Haskell2010